Republican U.S. Senate candidates Terrence Wall and Dave Westlake said Wednesday that they'll stay in the race even if former Gov. Tommy Thompson jumps in.

Wall, a Madison developer, said he was "way too invested" in the campaign to drop out. Wall has lent some $275,000 to his campaign and hinted he might add more from his wallet. Westlake, who owns a Watertown-based printer cartridge business, said he's also in it for the long haul, regardless of what Thompson does.

Thompson, governor for 14 years and a former cabinet secretary for President George W. Bush, has suggested he might want to enter the GOP race against Democratic Sen. Russ Feingold. Recent polls show Thompson doing better against Feingold than Wall and Westlake.

Both were careful to praise Thompson, but Westlake also offered some criticism. He said Thompson initially endorsed the new health care reform legislation and as governor had presided over an expansion of state government.

Wall said he speaks to Thompson once a month or so and that the former governor had given him political advice. Asked whether he'd seek Thompson's endorsement if Thompson decides not to run for Senate, Wall said: "That's between the former governor and I."

Wall said he planned to spend $7 million to $10 million in the race, including some of his money. He said it would take a lot of money to beat Feingold and noted that Westlake's fund raising had lagged.

Westlake and Wall spoke during a forum sponsored by the Milwaukee Press Club.

Both described themselves as small-government conservatives, who favored less taxation and government regulation. Both spoke admiringly of the tea party movement. Wall said the group's actions could be a deciding factor in the November elections.

Wall defended his record of paying no personal state income taxes for several years, saying he took advantage of legal tax breaks recommended by his accountant.

"We pay all the taxes that we owe," Wall said. He has said business losses had offset his state income taxes some years.

Wall said he favors substitution of a so-called flat income tax, which charges a single rate and eliminates loopholes. Westlake said he favored a tax on consumption as an alternative to the current income tax system.

Wall said he regretted having made political donations to two Wisconsin Democrats, U.S. Reps. Dave Obey and Tammy Baldwin. He said he was proud to be one of the larger Republican contributors nationally and that 96% of his contributions had gone to Republicans.